Photographic developer



Patented Feb; 16, i943 PATENT OFFICE r'no'rocmrmc nn'vnmrnn William H. Wood, Bcdford, Ohio, assignor to 'Han'is-Scybold-Potter a Company,

Cleveland,

Ohio, a corporation of Ohio No Drawing. Application December 6, 1939, Serial No. 307,863

Claims. =(c1. 95-48) g This invention relates to photography, and more particularly developers; and it is among the objects of the invention to improve developing procedure and compositions, and more particularly facilitate development of the so-called fine grain" character.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particu larly pointed out in the claims, the following description setting forth in. detail certain illustrative embodiments of the invention, these being indicative however, of but a few of the various. ways in which the principle of the invention may be employed.

In accordance with my invention, a developing composition is made. up to include piperazine and a silver halide developing agent. The piperazine may be in convenient or desired form, either anhydrous or crystalline, the latter form being more generally preferable on account of its very ready solubility, and I especially prefer Piperazine hexahydrate grams 10 Paraphenylenediamine --do 16 Glycine do Sodium sulphite do 90 Potassium bromide do 0.33 Water Y liters 1.2

The developing is carried out at customary developing temperature, usually around 70 or -75 E, but the composition is not critical as to temperature.

Also the present compounds'are particularly advantageous with one or more of the aminohydroxy compounds described in my co-pendlng application Serial No. 307,865, viz. an alkyl substituted amino-hydroxy aliphatic compound sufliciently soluble for working. concentratiomf Presence of a sulphite radical is also desirable.

As an illustrative example, the following is given:

Piperazine hexahydrate grams l0 Paraphenylenediamine do 16 Glycine do 15 Sodium sulphite do 90 Trimethylolaminomethane do 2.5 Potassium bromide do 0.3 Water liters 1.2

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims,

or the equivalent of such, be employed.

- glycine, paraphenylenediamine, sodium sulphite .tinctly claim as my invention:

I therefore particularly point out and disl. In preparing photographic images, developing the image in the presence of piperazine,

and potassium bromide.

2. In preparing photographic images, developing the image in the presence of piperazine,

an aliphatic amino compound of the general formula R -c-cmon in which R is an alkyl radical and R is an alkyl which optionally may have a hydroxyl suiliciently soluble for working concentration, a compound providing a sulphite radical, and a silver halide developing agent of fine grain type.

3. In preparing photographic images, developing the image ln the presence ,of piperazine,

an aliphatic amino compound of the general formula lv-c-cnlon l IHr in which R'is an alkyl radical and R is an alkyl which optionally may have a hydroxyl suiilciently soluble for working concentration, and a silver halide developing agent.

4. In preparing photographic images, developing the image in the presence of piperazine which optionally may have a hydroxyl sumclently soluble for working concentration, a. compound providing a aulphite radic'el, and a silver halide developing agent of fine grain ty-pe.

per a'mm silver halide developing:

devel-' sodium- 8. A photographic developer containing piperazine; an aliphatic amino compound d the general" formula in which R is-an'alkyl'mdical and R" is an alkyl which optionally may have a hydroxyl sumcientiy soluble for working concentration; and a silver-1 halide developin a ent;

9. A hotographic "developer-containing iper- .l azine 0.5 to 51) percent and; silver halidedevel opihgsagent of nnegrain t'ype; V

10. A photographic developer oontaininlv p n azine 0.5 to 5.0'per cent snd'a-silvershalide devei opingcgent.

WILLEIAM H. WOOD. 

